Chili Peppers and Child Birth

A recent manuscript in Cell Reports from the Zakharian lab demonstrates that the peptide hormone oxytocin activates the heat-sensing channel TrpV1.

Oxytocin is the hormone that signals contractions of the uterine muscle during child birth, and milk letdown during lactation. Typically, oxytocin signals by activating a G-protein coupled receptor, OXTR, which couples to signaling pathways to evoke Ca2+ release from the endoplasmic reticulum. Curiously, it’s long been noted that oxytocin accumulates in parts of the brain that lack OXTR expression, suggesting that the hormone may signal through OXTR-independent pathways.

In this report, Zakharian and colleagues demonstrate that oxytocin application to cells expressing TrpV1 but not the OXTR, altered TrpV1 currents. TrpV1 channels are best known for their activation by high temperatures and capsaicin, the active component of chili peppers. Intriguingly, following prolonged activation, TrpV1 channels are desensitized resulting in pain relief. A role for oxytocin in the regulation of TrpV1 channels may indicate that oxytocin induced desensitization of TrpV1 may play an important role in pain relief.